The standard tolower() / toupper() take a single character only; bulk strlwr() / strupr() are nonstandard (if commonly present) and—more importantly—virtually u

The standard tolower() / toupper() take a single character only; bulk strlwr() / strupr() are nonstandard (if commonly present) and—more importantly—virtually unused. I suppose implementing this technique in the C/POSIX-locale version of nonstandard stricmp() / POSIX strcasecmp() might be helpful in some cases, because people do use that one, but I still expect that any situations that truly call for an ASCII-only case-insensitive comparison (parsers?) will be doing much more work per byte for other reasons (state machine, perfect hash, etc.).